2000 Z28 4L60E Hits the rev limiter every time 1-2, 2-3 shifts. Will bang the limiter 4/5 times and then shift or never shift at all untill you let off the throttle. The trans was rebuilt with a mild shift kit and a 1900 converter. The engine is built with stage 2 ls6 heads/ comp cam, fast intake, the normal stuff. The trans rebuilder says its the tune and the tuner says its the trans. 1900 converter is nothing and should have no conveter shift problems at all. The PCM has been worked over for days with no results. The engine rev limiter is 6700 and the trans has been set to shift as low as 4000 a wot and still bangs the limiter and no shift. MPH was set as low as 10 to make it ready way early. Logging MPH and RPM and setting them to shift proper did nothing. Lowering shift times and increasing pressures has done nothing. Replacing stock program did nothing. When not at WOT shifts all occure on time and are ok, maby a little soft for my taste but ok. Transmission pressures are as follows all at operating temp
100psi in park
140 reverse
260 park with electrical connector unpluged from trans
100 highway cruising l0% TPS
200 is the highest I see when driving and that is all in at about 30% throttle crusing along more throttle still gives about 200 but the needle starts shaking around and not steady
200 WOT 4-3 downshift at high speed to keep out of 2nd
100 WOT 4-2 downshift Goes from 4th to 2nd and the gauge goes all over it spikes to about 300 for a split secound and then the needle goes all over from 100 to 250 by the time it hits the rev limiter its at 100 steady
Using the scanner I get this info
.76 amps at 200 psi when 30% throttle
1.04 amps at 100 psi idle
.47 amps at wot in 2nd on my way to hit the limiter and gauge going crazy and steadying at 100

During a wot 1-2 shift the scanner tells me that I am in 1st and then at the programmed rpm it tells me that I am in 2nd but the shif never happens and the 1-2 2-3 solenoids are both reading on. If the shift ever happens I see the 1-2 go off.
This is the same thing with the 2-3 shift

I also had these codes for the transmission.
1860,740, 748, 785, 1810. I cleared them out and after 50 miles the only code that came back on was 748 for the pressure control solenoid

The PCS was replaced in the rebuild. I have another LS1 car with 440rwhp and a Yank 3600 that never hits the rev limiter and the shift is 200rpm before the limiter.

It looks like the pressure is going south when wot, the pressure is nice and steady most of the time and will raise and lower with TPS. But at WOT the needle starts moving all over and settling at a low 100.

Help

 

oddly not sure if will have affect on the shift at WOT since the scanner says both solenoids are on till the shift occurs so that means that issue is still in the tuning somewhere. But I did have a guy recently who called me and said he solved that issue by turning off kickdown in the settings but worth a try and he did still actually have kickdown when he go on it,
As for the pressure jumping wildly at WOT high line I have sen this many times on the DYNO ad a quart of fluid it will likely stabilize.
Hope this helps some

 

That is very good and useful information. What Tuning software is being used? If you are using EFI Live I don't mind looking at the .bin file to see if I would do anything different. Also, send me any data logged passes if you have them. Send that info to gilbert@aceracingtrans.com .

How long is it taking for the shifts to occur once they have been commanded? This should be a default PID if I'm not mistaken.

Low fluid can wreak havoc on one of these units, but the pressure would not level off IMHO. This is a very good example of why we run a vacuum modulator instead of an EPC solenoid.

This comment tells me that the shifts are being commanded, but are not taking place. If I had to take a swing at this issue I would have to say you are experiencing Shift Solenoid Flooding, the solenoids are being suppled more fluid than they can flow. Therefore until they exhaust properly the shift is not occurring.

What changes were made to the valve body plate solenoid feed holes during the shift kit install? Which shift kit was installed?

g

 

Using HPTuner. I just installed a stock none touched PCM in the car and had the same results just hitting the rev limiter at the stock RPM. I also thought the same thing about the solenoids not being able to exhaust because of high line pressure. The fluid level is full and the car has been doing this for three months. After head/cam and gears the car would hit the rev limiter once and then shift every now and then. New trans and it is all the time and no shift, have to let off to shift. The fluid pressure goes crazy with the needle bouncing from 100 to 300 and finally once hitting the rev limiter it will normally just hang at 100. I tuned a few things just to see what would happen, like increasing pressure in the lower torque range. On a stock Z this would give some nice hard tire chirps on this trans nothing, just a stock feel. I am a third party in this, its a new customers car for me. The trans was built at one shop and the head/cam/program at another. He started looking for a different shop because these two couldn't work it out. I just happen to do both tranmissions and tuning. I have done everything and nothing works. I have a few hours into this car and can't charge for a no fix and I don't really want to dig into another shops rebuild. You never know what they did and that can always lead to more fun.

 

If you installed a shift kit you may have to delete torque mgt.

 

This above is what interest me about the issue where you show that the pcm says second but at the same time shows both solenoids as on which would be first, If it was solenoid flooding the solenoids would still turn off so If I am understanding this correctly from what your saying the PCM commands second in the programing but at the same time does not turn off the shift solenoid A (1-2) ?

But I have seen the 4L60E even in the crosshatch have pressure loss and spikes at HI LINE and RPM due to the pan emptying on several occasions pulling air into the system causing erratic line and have solved it by filling to just at or slightly above the cross hatch on the stick I have seen this both in real world and on the dyno. The 60E unless it has a deep pan has almost no reserve fluid capacity. I have see them neutral at the track due to this even with the fluid read mid crosshatch with cars with a strong 60ft.

 

Well I know the rock and a hard place you are at... see that scenario play out very often around here. My first thoughts would be to sell tear down and disassembly time. I believe the shift kit is where you'll find you're issues. Either way, I feel like you have mechanical issues internally related to pressure.

Good Luck.

g